To date, various antibiotics and synthetic antibacterial agents have been used for treatment of infectious diseases in the medical field. However, in recent years, resistant bacteria such as methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus (VRE), penicillin-resistant Streptococcus pneumoniae (PRSP), quinolone-resistant Escherichia coli, carbapenem-resistant Klebsiella pneumoniae, or multiple drug resistant Pseudomonas aeruginosa have appeared. Since these resistant bacteria are resistant to many of the existing antibiotics and antibacterial agents, the treatment of patients affected with these resistant bacteria has assumed a global importance.
Accordingly, there is a need for the development of an antibacterial agent in a different category, which has a structure different from those of the existing antibacterial agents.
As such antibacterial compounds in a different category, a group of compounds are known which have two aromatic rings that may be heterocyclic rings, and which comprise a heterocyclic ring, such as oxazolidinone, as a structural moiety for connecting these aromatic rings to each other (see Patent Literature 1 to 12, for example). However, it is considered that the compounds having such a structure must be improved in terms of safety, in order to apply them to the clinical field. With regard to the compounds of the above-described structure, a compound has not been known having a structure in which pyrrolidinone is comprised in the structure connecting the two aromatic rings.